Kris Holm unicycle rims
These would be perfect – only in 36 hole though.
They also do one without cut outs for £35.

Onza do a 45mm with cut outs that works well

I’ve been doing some measuring and the biggest differences between the X King and the Dirt Wizard are the cost, the tread pattern and the weight. Volume, not so much…

All measurements round the casing with digital calipers, circumference rim hook to hook with thread and tape measure.

Front “2.75” Dirt Wizard on Crest. 20 psi
Width (digital calipers) – 2.35 in
height from rim hook (d.c.) – 2.05 in
circumference (thread and tape measure) – 6.5 in

Rear “2.4” X-King on Crest 20 psi
Width – 2.33 in
height from rim hook – 1.91 in
circumference – 6.25 in

Dirt Wizard is 850g in the light weight version and costs £65
X King is 560g in light weight version, costs £35
Admittedly the tread is chunkier and is going to take a lot of that extra weight.

A 39 mm (internal) Velocity Dually is 610g
21mm internal Crest is 340g

So you may as well get a wide rim and whatever tyre you fancy, but don’t think the Dirt Wizard is THE way to go for an extra volume. I did see a chap running the 2.4in X-kings on Duallys and they looked pretty substantial!

Maybe if I say “biff, biff, biff,” he’ll come and say how he likes them?

I think rider weights and style need to be taken into consideration.

If I ran crests with a 2.7″ tyre at 20psi I am sure it would all end in tears …..

Exactly. Cost and weight wise:

http://singletrackworld.com/forum/topic/fat-front-v-normal-rigid-v-suss-fork

Just installed a Hans Damp 2.35 (the TrialStar snakeskin model) on a bonty rim (around 20mm). Comes up about the same as the X-king measurements above maybe slightly larger.

Very impressed with this tyre the sidewall is so strong I can run at 20psi and that a 13.5st bloke.

I think Vee Rubber make a 26 x 3″ tyre which might be worth looking at? Their prices are very reasonable, especially compared to Surly.